Blake in the meanwhile remained outside of Cadiz during the autumn and winter, till the spring of 1657, waiting for the next instalment of the Plate Fleet. It was an unheard-of thing at that time to keep a fleet out for the winter. Even now the heavier vessels had been sent home with Montagu and Stayner, but the persistence of the others in remaining abroad shows that our navy was increasing in seaworthiness and hardihood. In the April of 1657 Blake was rewarded for his perseverance by learning that a large Spanish squadron carrying treasure had taken refuge at Santa Cruz de Tenerife. To attack them in this port was in the general opinion an enterprise of the utmost hazard. The bay of Santa Cruz is deep and the island hilly, therefore the harbour is perpetually liable either to be in a dead calm, or to be swept by the violent gusts of wind off the land. These natural obstacles made entrance difficult for a fleet. And Santa Cruz was in addition very powerfully fortified. So strong, in fact, had art and nature made the harbour, that the Spaniards considered a successful attack impossible, and Blake's contemporaries looked upon his triumph as an unheard-of achievement of daring. Yet the Commonwealth admiral, like so many other men of strong mind, showed his strength by despising the vain appearance of force. He estimated the inefficiency of the Spaniards at its true value. Moreover, he saw that the forts, if attacked closely, would probably fail to stop the entry of a fleet running before a good breeze and borne on a rising tide. Once in the harbour, and in the midst of the Spanish vessels, he would be comparatively safe, since they would mask the fire of the guns on shore. With the turn of the tide, aided, as it was very likely to be, by one of the common winds off the land, he would be able to secure his retreat. No doubt there was an appreciable risk, as there always must be in the serious operations of war. But it was one a bold man commanding an effective fighting force could run without temerity.